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Divergent catalytic behaviors of Pt and Pd films in the cathode of a sandwiched type membrane reactor

Paper ID Volume ID Publish Year Pages File Format Full-Text
46886 46452 2011 8 PDF Available
Title
Divergent catalytic behaviors of Pt and Pd films in the cathode of a sandwiched type membrane reactor
Abstract

Relative electrochemical and catalytic hydrogenation responses to NO3− reduction by the Ag modified Pt, Pd and Pt–Pd cathodes, deposited on H+ conducting Nafion membrane, have been studied. The electrochemical investigations noticed the maximum reactivity to show by an Ag–Pt electrode exhibiting a reduction current of 24.26 mA cm−2 at −1.26 V vs. Ag/AgCl reference electrode. Conversely, the catalytic hydrogenation reaction exhibited maximum nitrate reduction rate by an Ag–Pd catalyst having a rate constant of 25.1 × 10−3 min−1. While both electrochemical reactions and catalytic hydrogenation reactions were combined in the electrolyte reactor, the highest reduction efficiency was found to show by an Ag–Pt–Pd cathode assembly, where the reduction current was 20.12 mA cm−2 and the rate constant was 84.3 × 10−3 min−1 under controlled current electrolysis condition. In this paper, reasons of such divergent catalytic behaviors have been discussed.

Graphical abstractProposed schematic representation of NO3− reduction mechanism in the membrane reactor preferentially occurred by the Ag–Pt and Ag–Pd sites. On the cathode surface, Pt particles mainly reduced nitrate ions by heterogeneous electron transfer reaction. Here the Ag acted as electron promoting particles. By contrast, Pd reduced nitrate ions mainly by hydrogenation reactions. Water is splitted on the Pt anode surface generating H+, which is migrated to the cathode surface through the 180 μm thick H+ conducting.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► In the reactor, most active cathode is Ag–Pt–Pd. ► Ag–Pt favored electron transfer reaction. ► Ag–Pd favored hydrogenation reaction.

Keywords
Nitrate reduction; Catalytic hydrogenation; Rate constant; Voltammetry, Selectivity
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 107, Issues 3–4, 21 September 2011, Pages 294–301
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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Any Questions? feel free to contact us